In NAND flash memory, when the total number of errors in a codeword is larger than the error correction capability of error correcting code (ECC), ECC will fail to correct the stored data. If the data ECC fails to correct is important data (e.g., meta data and/or file system data), the whole solid state drive (SSD) may become unusable. If the SSD becomes unusable then other data may be lost.
It would be desirable to implement data recovery when ECC fails to correct data in a SSD controller and/or drive.